Improve cache_size and cache_size_percent descriptions

modules/reference/pages/properties/object-storage-properties.adoc

@@ -317,7 +317,17 @@ Divide the object storage cache across the specified number of buckets. This onl
 
 === cloud_storage_cache_size
 
-Maximum size of object storage cache. If both this property and <<cloud_storage_cache_size_percent,cloud_storage_cache_size_percent>> are set, Redpanda uses the minimum of the two.
+Maximum size of the object storage cache, in bytes.
+
+This property operates along with <<cloud_storage_cache_size_percent,`cloud_storage_cache_size_percent`>>:
+
+- When both properties are set, Redpanda uses the smaller calculated value of the two, in bytes.
+
+- If one of these properties is set to `0`, Redpanda uses the non-zero value.
+
+- These properties cannot both be `0`.
+
+*Unit*: bytes
 
 *Requires restart:* No
 
@@ -333,7 +343,15 @@ Maximum size of object storage cache. If both this property and <<cloud_storage_
 
 === cloud_storage_cache_size_percent
 
-Maximum size of the cloud cache as a percentage of unreserved disk space disk_reservation_percent. The default value for this option is tuned for a shared disk configuration. Consider increasing the value if using a dedicated cache disk. The property <<cloud_storage_cache_size,`cloud_storage_cache_size`>> controls the same limit expressed as a fixed number of bytes. If both `cloud_storage_cache_size` and `cloud_storage_cache_size_percent` are set, Redpanda uses the minimum of the two.
+Maximum size of the cache as a percentage, minus the space that Redpanda avoids using defined by the xref:reference:cluster-properties.adoc#disk_reservation_percent[`disk_reservation_percent`] cluster property. This is calculated at startup and dynamically updated if either this property or  <<cloud_storage_cache_size,`cloud_storage_cache_size`>> changes.
+
+This property operates along with <<cloud_storage_cache_size,`cloud_storage_cache_size`>>:
+
+- When both properties are set, Redpanda uses the smaller calculated value of the two, in bytes.
+
+- If one of these properties is set to `0`, Redpanda uses the non-zero value.
+
+- These properties cannot both be `0`.
 
 *Unit:* percent